Estimated Tipping Guidelines?

I'm trying to get an idea of how much I will need to tip my vendors.

Are you guys tipping 20% straight across the board?

My photog and DJ own their businesses so I was thinking maybe give them a little less then 20%? Or no?

No, I dont think you need to tip 20% across the board...esp if it's the vendor's own business.

Here's a helpful tipping thread

tipping thread